Validity and Reliability of the Korean Version of the Arthritis Impact Measurement Scales 2 (Korean-AIMS2) in Patients with Osteoarthritis

ABSTRACT

BACKGROUND: The second version of the Arthritis Impact Measurement Scales (AIMS2) is an improvement on an evaluation instrument that was developed to measure patient outcome in the rheumatic diseases. The goal of this study was to validate a translated version of the revised and expanded Arthritis Impact Measurement Scales (AIMS2) to be used by Korean patients with osteoarthritis (OA) of the knee. METHODS: The AIMS2 was translated into Korean according to a recommended translation guideline. The Korean version of AIMS2 (K-AIMS2) was administered to a cohort of 239 outpatients with symptomatic OA of the knee who attended 7 participating University Hospitals in Seoul, Ilsan and Taejon. Forty eight patients readministered the K-AIMS2, 7 days after the first visit, to evaluate the instrument's test-retest reliability. After 6 weeks of NS AIDs therapy, 79 subjects were asked to complete a second survey of the questionnaire. RESULTS: The internal consistency reliability of each scale score, as estimated by Cronbach's alpha coefficient, was high and indicated that the components of the scale measured the same construct. The items were all correlated with each other, but there was no redundancy; this indicated that each domain addressed a somewhat different aspect of functional disability. The test-retest reliability equalled or exceeded 0.86 for 12 scales. Factor analysis provided a three-factor health status model explaining 58.2% of the variance. The upper limb function scales formed the first factor. Psycho-social scale were loaded on the second factor. Arthritis pain together with physical scales for mobility level and walking and bending were loaded on the third factor (the lower limb function). The scale for support from family and friends was not loaded on any factors. These results demonstrate that the physical health status scales of the K-AIMS2 are valid, as shown by the significant, moderate to high correlations between the K-AIMS2 subscales and the majority of the clinical measures. CONCLUSION: Our data suggest that, like the original questionnaire, the Korean version of AIMS2 is a reliable, consistent and valid instrument for measuring health status and physical functioning in patients with OA of the knee.